Study of Cobimetinib in Participants With Solid Tumors

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This non-randomized, open-label, study will determine the highest safe dose of cobimetinib, how often it should be taken, how well participants with cancer tolerate cobimetinib and will assess the pharmacokinetic effect of midazolam and dextromethorphan on the study drug.

Participants will receive cobimetinib (GDC-0973/XL518) at the starting dose of 0.05 mg/kg via solution or capsule, once daily for Days 1-21 of each 28-day cycle (21 days on drug followed by 7 days off treatment [21/7 schedule]). Treatment will continue until progressive disease (PD) or unacceptable toxicity for up to 1 year at the discretion of investigator and beyond 1 year with the agreement of the sponsor.

Drug: cobimetinib

Repeating oral dose

Other Name: GDC-0973/XL518

Experimental: Stage 1A: Cobimetinib Dose Escalation (14/14 Schedule)

Participants will receive cobimetinib at the starting dose of 60 mg via solution or capsule, once daily for Days 1-14 of each 28-day cycle (14 days on drug followed by 14 days off treatment [14/14 schedule]). Treatment will continue until progressive disease (PD) or unacceptable toxicity for up to 1 year at the discretion of investigator and beyond 1 year with the agreement of the sponsor.

Drug: cobimetinib

Repeating oral dose

Other Name: GDC-0973/XL518

Experimental: Stage 2: Cobimetinib Expansion (21/7 Schedule)

Participants will receive cobimetinib at the maximum tolerated dose (MTD) established in Stage 1, once daily for Days 1-21 of each 28-day cycle (21 days on drug followed by 7 days off treatment [21/7 schedule]). Treatment will continue until progressive disease (PD) or unacceptable toxicity for up to 1 year at the discretion of investigator and beyond 1 year with the agreement of the sponsor.

Drug: cobimetinib

Repeating oral dose

Other Name: GDC-0973/XL518

Experimental: Stage 2 A: Cobimetinib Expansion (14/14 Schedule)

Participants will receive cobimetinib at the MTD established in Stage 1A, once daily for Days 1-14 of each 28-day cycle (14 days on drug followed by 14 days off treatment [14/14 schedule]). Treatment will continue until progressive disease (PD) or unacceptable toxicity for up to 1 year at the discretion of investigator and beyond 1 year with the agreement of the sponsor.

Drug: cobimetinib

Repeating oral dose

Other Name: GDC-0973/XL518

Experimental: Stage 3: Cobimetinib+Midazolam+Dextromethorphan

Participants will receive a single dose of midazolam (2 mg of midazolam syrup) and dextromethorphan (30 mg tablet) on Cycle 1 Day 1, in the absence of cobimetinib. After a 2-day washout period, participants will receive 21 consecutive daily doses of cobimetinib (60-mg) followed by a 7-day washout period. Participants will receive another single dose of midazolam and dextromethorphan on Cycle 1 Day 15, in the presence of steady-state cobimetinib concentrations. In Cycle 2 and beyond participants will receive cobimetinib alone, administered as a 60-mg daily dose for 21 consecutive days in 28-day cycles (21/7 schedule).

Stage 1 and 1A: Number of Participants With Dose Limiting Toxicities (DLTs) [ Time Frame: Stage 1 and 1A: Days 1 to 28 of Cycle 1 ]

Adverse events (AE) were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE) v3.0. DLT was defined as either of the following occurring during the Study Treatment Period. The occurrence of a drug-related AE that, in the opinion of the cohort review committee (CRC), was of potential clinical significance such that further dose escalation would expose participants in higher dose cohorts to risk of irreversible medical harm or require medical treatment to avoid irreversible medical harm or non-hematologic toxicity

AEs were graded according to the NCI-CTCAE v3.0. A DLT was determined from clinical findings during the Study Treatment Period (Cycle 1, Days 1). MTD was defined as the dose at which no DLTs were observed. DLT was defined as either of the following occurring during the Study Treatment Period. The occurrence of a drug-related AE that, in the opinion of the CRC, was of potential clinical significance such that further dose escalation would expose participants in higher dose cohorts to risk of irreversible medical harm or require medical treatment to avoid irreversible medical harm or non-hematologic toxicity

AEs were graded according to NCI-CTCAE v3.0. A DLT was the basis for determining MTD in Stage 1A participants. The participants of Stage 1A are dose-escalation cohorts, starting at the MTD of the 21/7 schedule, were treated on a 14/14 schedule to determine the MTD. A DLT was defined as either of the following occurring during the Study Treatment Period:

Occurrence of a drug-related AE that, in the opinion of the CRC, was of potential clinical significance such that further dose escalation would expose participants to risk of irreversible medical harm; Nonhematologic toxicity: Grade 3 or 4 events, including Grade 3 nausea and/or vomiting and/or Grade 3 diarrhea, despite prophylaxis and/or treatment; Hematologic toxicity: Grade 4 thrombocytopenia. Grade 4 neutropenia of more than 4 days' duration; Grade 4 neutropenia of any duration with fever or documented infection. AEs (Grade 3 or higher) for which a clinical cause unrelated to cobimetinib was evident was not considered DLTs.

The area under the concentrations-time curve (AUC0-24) was calculated with the measured data points from the time of administration of cobimetinib up to 24 h after administration by the trapezoidal formula. AUC 0-24 is the truncated AUC over a 24-hour sampling interval. The concentration-time curve is the result of time points of blood sampling and its measured concentration of free cobimetinib in the blood samples. AUC is measured as hours times nanograms per milliliter (h*ng/mL).

The area under the AUC0-24 for steady state in stage 1 was calculated with the measured data points from the time of administration of cobimetinib up to 24 h after administration by the trapezoidal formula. AUC 0-24 is the truncated AUC over a 24-hour sampling interval. The concentration-time curve is the result of time points of blood sampling and its measured concentration of free cobimetinib in the blood samplings.

Clearance of a drug is a measure of the rate at which a drug is metabolized or eliminated by normal biological processes. Drug clearance is a quantitative measure of the rate at which a drug substance is removed from the blood. Apparent clearance was calculated only for participants who had a quantifiable AUC 0-24 in steady state.

AUC0-24 for stage 1A was calculated on Day 1 with the measured data points from the time of administration of cobimetinib up to 24 h after administration by the trapezoidal formula. AUC 0-24 is the truncated AUC over a 24-hour sampling interval. The concentration-time curve is the result of time points of blood sampling and its measured concentration of free cobimetinib in the blood samplings.

Clearance of a drug is a measure of the rate at which a drug is metabolized or eliminated by normal biological processes. Drug clearance is a quantitative measure of the rate at which a drug substance is removed from the blood. Apparent clearance was calculated only for participants who had a quantifiable AUC 0-24 in steady state.

The area under the AUC0-24 for steady state in stage 1A was calculated with the measured data points from the time of administration of cobimetinib up to 24 h after administration by the trapezoidal formula. AUC 0-24 is the truncated AUC over a 24-hour sampling interval. The concentration-time curve is the result of time points of blood sampling and its measured concentration of free cobimetinib in the blood samplings.

The area under the AUC0-24 on Day 1 in stage 2 was calculated with the measured data points from the time of administration of cobimetinib up to 24 h after administration by the trapezoidal formula. AUC 0-24 is the truncated AUC over a 24-hour sampling interval. The concentration-time curve is the result of time points of blood sampling and its measured concentration of free cobimetinib in the blood samplings.

The area under the AUC0-24 for steady state in stage 2 was calculated with the measured data points from the time of administration of cobimetinib up to 24 h after administration by the trapezoidal formula. AUC 0-24 is the truncated AUC over a 24-hour sampling interval. The concentration-time curve is the result of time points of blood sampling and its measured concentration of free cobimetinib in the blood samplings.

Clearance of a drug is a measure of the rate at which a drug is metabolized or eliminated by normal biological processes. Drug clearance is a quantitative measure of the rate at which a drug substance is removed from the blood. Apparent clearance was calculated only for participants who had a quantifiable AUC 0-24 in steady state.

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Ages Eligible for Study:

18 Years and older (Adult, Senior)

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

No

Criteria

Inclusion Criteria:

Histologically confirmed solid tumor that is metastatic or unresectable, and for which standard curative or palliative measures do not exist or are no longer effective, and there are no known therapies to prolong survival

Disease that is measurable according to Response Evaluation Criteria in Solid Tumors (RECIST)

Adequate organ and marrow function

Sexually active participants must use medically acceptable methods of contraception during the course of the study and at least 11 days after the last dose of study treatment

Female participants of childbearing potential must have a negative serum pregnancy test at screening

No other history of/or ongoing malignancy that would potentially interfere with the interpretation of the pharmacodynamic or efficacy assays

Exclusion Criteria:

Anticancer treatment (e.g., chemotherapy, radiotherapy, cytokines, or hormones) within 28 days (6 weeks for nitrosoureas or mitomycin C, or 14 days for hormonal therapy or kinase inhibitors) before the first dose of study drug

The participant has not recovered to Grade </=1 from adverse events (AEs) or to within 10% of baseline values due to investigational or other agents administered more than 28 days prior to study enrollment

The participant has received another investigational agent within 28 days of the first dose of study drug